Avoid calling QCompleter::popup() internally

QCompleter::popup() is used to lazily create the popup itself.
However, we oftentimes call this function only to check if the
popup is visible.

Change-Id: I55531e1e6810c02a44f5f65124cf641b1a89de69
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

src/widgets/util/qcompleter_p.h

@@ -101,6 +101,9 @@ public:
     void _q_autoResizePopup();
     void _q_fileSystemModelDirectoryLoaded(const QString &path);
     void setCurrentIndex(QModelIndex, bool = true);
+
+    static QCompleterPrivate *get(QCompleter *o) { return o->d_func(); }
+    static const QCompleterPrivate *get(const QCompleter *o) { return o->d_func(); }
 };
 
 class QIndexMapper

src/widgets/widgets/qcombobox.cpp

@@ -71,6 +71,7 @@
 #include <private/qabstractitemmodel_p.h>
 #include <private/qabstractscrollarea_p.h>
 #include <private/qlineedit_p.h>
+#include <private/qcompleter_p.h>
 #include <qdebug.h>
 #if 0 /* Used to be included in Qt4 for Q_WS_MAC */ && QT_CONFIG(effetcts) && QT_CONFIG(style_mac)
 #include <private/qcore_mac_p.h>
@@ -3140,13 +3141,13 @@ void QComboBox::keyPressEvent(QKeyEvent *e)
     Q_D(QComboBox);
 
 #if QT_CONFIG(completer)
-    if (d->lineEdit
-        && d->lineEdit->completer()
-        && d->lineEdit->completer()->popup()
-        && d->lineEdit->completer()->popup()->isVisible()) {
-        // provide same autocompletion support as line edit
-        d->lineEdit->event(e);
-        return;
+    if (const auto *cmpltr = completer()) {
+        const auto *popup = QCompleterPrivate::get(cmpltr)->popup;
+        if (popup && popup->isVisible()) {
+            // provide same autocompletion support as line edit
+            d->lineEdit->event(e);
+            return;
+        }
     }
 #endif
 

src/widgets/widgets/qwidgetlinecontrol.cpp

@@ -44,6 +44,7 @@
 #endif
 #include "qclipboard.h"
 #include <private/qguiapplication_p.h>
+#include <private/qcompleter_p.h>
 #include <qpa/qplatformtheme.h>
 #include <qstylehints.h>
 #ifndef QT_NO_ACCESSIBILITY
@@ -1484,7 +1485,8 @@ void QWidgetLineControl::complete(int key)
     } else {
 #ifndef QT_KEYPAD_NAVIGATION
         if (text.isEmpty()) {
-            m_completer->popup()->hide();
+            if (auto *popup = QCompleterPrivate::get(m_completer)->popup)
+                popup->hide();
             return;
         }
 #endif
@@ -1630,10 +1632,10 @@ void QWidgetLineControl::processKeyEvent(QKeyEvent* event)
 #if QT_CONFIG(completer)
     if (m_completer) {
         QCompleter::CompletionMode completionMode = m_completer->completionMode();
+        auto *popup = QCompleterPrivate::get(m_completer)->popup;
         if ((completionMode == QCompleter::PopupCompletion
              || completionMode == QCompleter::UnfilteredPopupCompletion)
-            && m_completer->popup()
-            && m_completer->popup()->isVisible()) {
+            && popup && popup->isVisible()) {
             // The following keys are forwarded by the completer to the widget
             // Ignoring the events lets the completer provide suitable default behavior
             switch (event->key()) {
@@ -1648,7 +1650,8 @@ void QWidgetLineControl::processKeyEvent(QKeyEvent* event)
                 if (!QApplication::keypadNavigationEnabled())
                     break;
 #endif
-                m_completer->popup()->hide(); // just hide. will end up propagating to parent
+                popup->hide(); // just hide. will end up propagating to parent
+                break;
             default:
                 break; // normal key processing
             }